Publications by authors named "Ghareb M Soliman"

30 Publications

  • Page 1 of 1

Epigallocatechin-3-Gallate-Loaded Gold Nanoparticles: Preparation and Evaluation of Anticancer Efficacy in Ehrlich Tumor-Bearing Mice.

Pharmaceuticals (Basel) 2020 Sep 18;13(9). Epub 2020 Sep 18.

Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut 71526, Egypt.

Epigallocatechin-3-gallate (EGCG) is a pleiotropic compound with anticancer, anti-inflammatory, and antioxidant properties. To enhance EGCG anticancer efficacy, it was loaded onto gold nanoparticles (GNPs). EGCG-GNPs were prepared by a simple green synthesis method and were evaluated using different techniques. Hemocompatibility with human blood and in vivo anticancer efficacy in Ehrlich ascites carcinoma-bearing mice were evaluated. EGCG/gold chloride molar ratio had a marked effect on the formation and properties of EGCG-GNPs where well-dispersed spherical nanoparticles were obtained at a molar ratio not more than 0.8:1. The particle size ranged from ~26 to 610 nm. High drug encapsulation efficiency and loading capacity of ~93 and 32%, respectively were obtained. When stored at 4 °C for three months, EGCG-GNPs maintained over 90% of their drug payload and had small changes in their size and zeta potential. They were non-hemolytic and had no deleterious effects on partial thromboplastin time, prothrombin time, and complement protein C3 concentration. EGCG-GNPs had significantly better in vivo anticancer efficacy compared with pristine EGCG as evidenced by smaller tumor volume and weight and higher mice body weight. These results confirm that EGCG-GNPs could serve as an efficient delivery system for EGCG with a good potential to enhance its anticancer efficacy.
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http://dx.doi.org/10.3390/ph13090254DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7559993PMC
September 2020

Polymeric micelles for the ocular delivery of triamcinolone acetonide: preparation and evaluation in a rabbit ocular inflammatory model.

Drug Deliv 2020 Dec;27(1):1115-1124

Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut, Egypt.

The aim of this study was to prepare triamcinolone acetonide (TA)-loaded poly(ethylene glycol)--poly(ε-caprolactone) (PEG--PCL) and poly(ethylene glycol)--poly(lactic acid) (PEG--PLA) micelles as a potential treatment of ocular inflammation. The micelles were evaluated for particle size, drug loading capacity and drug release kinetics. Selected micellar formulations were dispersed into chitosan hydrogel and their anti-inflammatory properties were tested in rabbits using a carrageenan-induced ocular inflammatory model. Particle size ranged from 59.44 ± 0.15 to 64.26 ± 0.55 nm for PEG--PCL and from 136.10 ± 1.57 to 176.80 ± 2.25 nm for PEG--PLA micelles, respectively. The drug loading capacity was in the range of 6-12% and 15-25% for PEG--PCL and PEG--PLA micelles, respectively and was dependent on the drug/polymer weight ratio. TA aqueous solubility was increased by 5- and 10-fold after loading into PEG--PCL and PEG--PLA micelles at a polymer concentration as low as 0.5 mg/mL, respectively. PEG--PLA micelles suspended in chitosan hydrogel were able to sustain the drug release where only 42.8 ± 1.6% drug was released in one week. TA/PEG--PLA micelles suspended in chitosan hydrogel had better anti-inflammatory effects compared with the plain drug hydrogel or the drug micellar solution. Complete disappearance of the corneal inflammatory changes was observed for the micellar hydrogel. These results confirm the potential of PEG--PLA micelles suspended in chitosan hydrogel to enhance the anti-inflammatory properties of triamcinolone acetonide.
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http://dx.doi.org/10.1080/10717544.2020.1797241DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7470058PMC
December 2020

Liposomal and Ethosomal Gels for the Topical Delivery of Anthralin: Preparation, Comparative Evaluation and Clinical Assessment in Psoriatic Patients.

Pharmaceutics 2020 May 11;12(5). Epub 2020 May 11.

Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut 71526, Egypt.

To enhance anthralin efficacy against psoriasis and reduce its notorious side effects, it was loaded into various liposomal and ethosomal preparations. The nanocarriers were characterized for drug encapsulation efficiency, size, morphology and compatibility between various components. Optimum formulations were dispersed in various gel bases and drug release kinetics were studied. Clinical efficacy and safety of liposomal and ethosomal PluronicF-127 gels were evaluated in patients having psoriasis (clinicaltrials.gov identifier is NCT03348462). Safety was assessed by recording various adverse events. Drug encapsulation efficiency ≥97.2% and ≥77% were obtained for liposomes and ethosomes, respectively. Particle sizes of 116 to 199 nm and 146 to 381 nm were observed for liposomes and ethosomes, respectively. Fourier-Transform infrared (FT-IR) spectroscopy and differential scanning calorimetry (DSC) studies confirmed the absence of interaction between anthralin and various nanocarrier components. Tested gel bases showed excellent ability to sustain drug release. At baseline, the patients had a median Psoriasis Area and Severity Index (PASI) of 3.4 for liposomes and 3.6 for ethosomes without significant difference. After treatment, mean PASI change was -68.66% and -81.84% for liposomes and ethosomes, respectively with a significant difference in favor of ethosomes. No adverse effects were detected in both groups. Anthralin ethosomes could be considered as a potential treatment of psoriasis.
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http://dx.doi.org/10.3390/pharmaceutics12050446DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7285224PMC
May 2020

Latanoprost niosomes as a sustained release ocular delivery system for the management of glaucoma.

Drug Dev Ind Pharm 2020 May 23;46(5):806-813. Epub 2020 Apr 23.

Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut, Egypt.

Glaucoma is a leading cause of irreversible blindness worldwide. Whereas latanoprost is one of the most effective drugs in glaucoma treatment, its eye drops need frequent application leading to lack of patient adherence. This study aimed to develop a patient-friendly niosome-in-gel system for the sustained ocular delivery of latanoprost. Niosomes were prepared by the reverse-phase evaporation technique and optimized for different formulation parameters, such as cholesterol/surfactant and drug/surfactant ratios. Selected niosomal formulations were incorporated into different gels and their viscosity and drug release kinetics were evaluated. Optimal niosomal gel was evaluated in rabbits' eyes for irritation potential and ability to reduce intraocular pressure. FT-IR studies showed that there were nonspecific interactions between latanoprost and different niosomal components leading to drug encapsulation efficiency ≥88%. Latanoprost encapsulation efficiency increased with the drug/surfactant ratio and encapsulation efficiency ∼98% was obtained at a ratio of 50%. Pluronic F127 had the best ability to sustain drug release from the niosomes. In rabbits' eyes, this gel was free of toxic and irritant effects and reduced intraocular pressure over a period of three days, which was significantly longer than that of commercial latanoprost eye drops. Latanoprost niosomal Pluronic F127 gel may find applications in glaucoma management.
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http://dx.doi.org/10.1080/03639045.2020.1755305DOI Listing
May 2020

Colon-targeting of progesterone using hybrid polymeric microspheres improves its bioavailability and in vivo biological efficacy.

Int J Pharm 2020 Mar 23;577:119070. Epub 2020 Jan 23.

Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut 71526, Egypt; Department of Pharmaceutics, Faculty of Pharmacy, University of Tabuk, Tabuk, Saudi Arabia. Electronic address:

This study aims to enhance progesterone (PG) oral bioavailability via its incorporation into hybrid colon-targeted pectin/NaCMC microspheres (MS) cross-linked with Zn and Al. The MS were characterized for particle morphology, encapsulation efficiency, swelling behavior, drug release, mucoadhesivity and colon-specific degradability. Response-surface methodology was adopted to optimize the fabrication conditions. Enhancement of in vivo drug performance was evaluated through pharmacokinetic and pharmacodynamic studies. The optimized formulation was typically spherical with a mean diameter of 1031 µm and drug entrapment efficiency of 88.8%. This formulation exhibited pH-dependent swelling, negligible drug release in simulated gastric fluid and sustained-release pattern in simulated small intestinal fluid with a mean t of 26.5 h. It also showed prolonged and preferential adhesion to rat colonic mucosa, as well as expedited degradation in presence of rat caecal contents. The MS significantly increased the area under the curve and mean residence time by 1.8 and 2.3-fold, respectively compared to the free drug. Orally administered MS showed ~10 times increase in myometrial thickness compared with the drug suspension and elicited uterine responses very similar to that obtained parenterally. These results confirm the ability of this new carrier system to improve the oral bioavailability of PG and attain adequate clinical efficacy.
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http://dx.doi.org/10.1016/j.ijpharm.2020.119070DOI Listing
March 2020

Spironolactone-Loaded LeciPlexes as Potential Topical Delivery Systems for Female Acne: In Vitro Appraisal and Ex Vivo Skin Permeability Studies.

Pharmaceutics 2019 Dec 25;12(1). Epub 2019 Dec 25.

Department of Pharmaceutics, Faculty of Pharmacy, University of Tabuk, Tabuk 71491, Saudi Arabia.

Spironolactone (SP), an aldosterone antagonist with anti-androgen properties, has shown promising results in the treatment of female acne. However, its systemic side effects limit its clinical benefits. This study aimed to prepare and evaluate LeciPlexes for SP topical delivery. LeciPlexes were prepared by a one-step procedure and characterized using various techniques. Optimum LeciPlex preparation was incorporated into 1% methylcellulose gel and SP permeability was tested ex vivo in Sprague-Dawley rat skin. The maximum drug encapsulation efficiency obtained was 93.6 ± 6.9% and was dependent on the drug/phospholipid and surfactant/phospholipid ratios. A zeta potential of +49.3 ± 3.5 to +57.7 ± 3.3 mV and a size of 108 ± 25.3 to 668.5 ± 120.3 nm were observed for the LeciPlexes. FT-IR and DSC studies confirmed the incorporation of SP into the LeciPlexes through hydrophobic and hydrogen bonding interactions. SP release from the LeciPlex formulations was significantly slower than from the drug suspension. Cumulative SP permeated through rat skin from LeciPlex gel was about 2-fold higher than SP control gel. Cumulative SP deposited in the stratum corneum and other skin layers from the LeciPlex gel was about 1.8- and 2.6-fold higher than SP control gel, respectively. This new SP LeciPlex formulation is a promising carrier for the treatment of female acne.
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http://dx.doi.org/10.3390/pharmaceutics12010025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7022583PMC
December 2019

Soy isoflavone-loaded alginate microspheres in thermosensitive gel base: attempts to improve wound-healing efficacy.

J Pharm Pharmacol 2019 May 14;71(5):774-787. Epub 2019 Jan 14.

Department of Pharmaceutics, College of Pharmacy, Jouf University, Sakaka, Saudi Arabia.

Objectives: This study aims to develop thermosensitive gel containing soy isoflavone (antioxidant and anti-inflammatory natural agent) alginate microspheres for enhancement of wound-healing performance.

Methods: Soy isoflavone microspheres were prepared by ionic cross-linking method and optimized using the Box-Behnken optimization design. Formulations were characterized in terms of particle size, encapsulation efficiency and equilibrium swelling degree. The optimized formula was incorporated in Pluronic F127 gel base and examined for in vivo wound-healing efficacy.

Key Findings: Results showed mean particle size between 18 and 25 μm, encapsulation efficiency of over 75% and equilibrium swelling degree over 1.9. Thermal analysis indicated interaction between alginate and CaCl and embedding of soy isoflavone in microspheres. In vivo wound-healing efficacy showed significant advance in re-epithelization, mature collagen synthesis and proangiogenesis. Immunohistochemical investigation exhibited promising alpha-smooth muscle actin immunopositive cells expression, fibroblast activation and expression of proliferating cell nuclear antigen (proliferation marker) in the epidermis and in the dermis.

Conclusions: The developed formulation would appear to be a promising topical preparation for accelerating healing process.
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http://dx.doi.org/10.1111/jphp.13066DOI Listing
May 2019

Fluorouracil-Loaded Gold Nanoparticles for the Treatment of Skin Cancer: Development, in Vitro Characterization, and in Vivo Evaluation in a Mouse Skin Cancer Xenograft Model.

Mol Pharm 2018 06 7;15(6):2194-2205. Epub 2018 May 7.

Department of Pharmaceutics, Faculty of Pharmacy , Assiut University , Assiut 71526 , Egypt.

Fluorouracil (5-FU) is an antimetabolite drug used in the treatment of various malignancies, such as colon and skin cancers. However, its systemic administration results in severe side effects. Topical 5-FU delivery for the treatment of skin cancer could circumvent these shortcomings, but it is limited by the drug poor permeability through the skin. To enhance 5-FU efficacy against skin cancer and reduce its systemic side effects, it was loaded into a gold nanoparticle (GNP)-based topical delivery system. 5-FU was loaded onto GNPs capped with CTAB through ionic interactions between 5-FU and CTAB. GNPs were prepared at different 5-FU/CTAB molar ratios and evaluated using different techniques. GNP stability and drug release were studied as a function of salt concentration and solution pH. Optimum 5-FU/CTAB-GNPs were incorporated into gel and cream bases, and their ex vivo permeability was evaluated in mice dorsal skin. The in vivo anticancer efficacy of the same preparations was evaluated in A431 tumor-bearing mice. The GNPs had spherical shape and a size of ∼16-150 nm. Maximum 5-FU entrapment was achieved at 5-FU/CTAB molar ratio of 1:1 and pH 11.5. Drug release from GNPs was sustained and pH-dependent. 5-FU GNP gel and cream had around 2-fold higher permeability through mice skin compared with free 5-FU gel and cream formulations. Further, in vivo studies in a mouse model having A431 skin cancer cells implanted in the subcutaneous space showed that the GNP gel and cream achieved 6.8- and 18.4-fold lower tumor volume compared with the untreated control, respectively. These results confirm the potential of topical 5-FU/CTAB-GNPs to enhance drug efficacy against skin cancer.
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http://dx.doi.org/10.1021/acs.molpharmaceut.8b00047DOI Listing
June 2018

High payload nanostructured lipid carriers fabricated with alendronate/polyethyleneimine ion complexes.

Int J Pharm 2018 Jan 8;535(1-2):148-156. Epub 2017 Nov 8.

James L. Winkle College of Pharmacy, University of Cincinnati, Cincinnati, OH 45267 USA. Electronic address:

Oral bioavailability of the anti-osteoporotic drug alendronate (AL) is limited to ≤ 1% due to unfavorable physicochemical properties. To augment absorption across the gastrointestinal mucosa, an ion pair complex between AL and polyethyleneimine (PEI) was formed and incorporated into nanostructured lipid carriers (NLCs) using a modified solvent injection method. When compared to free AL, ion pairing with PEI increased drug encapsulation efficiency in NLCs from 10% to 87%. Drug release from NLCs measured in vitro using fasted state simulated intestinal fluid, pH 6.5 (FaSSIF-V2) was significantly delayed after PEI complexation. Stability of AL/PEI was pH-dependent resulting in 10-fold faster dissociation of AL in FaSSIF-V2 than measured at pH 7.4. Intestinal permeation properties estimated in vitro across Caco-2 cell monolayers revealed a 3-fold greater flux of AL encapsulated as hydrophobic ion complex in NLCs when compared to AL solution (P = 8.43 ± 0.14 × 10 cm/s and vs. 2.76 ± 0.42 × 10 cm/s). Cellular safety of AL/PEI-containing NLCs was demonstrated up to an equivalent AL concentration of 2.5 mM. These results suggest that encapsulation of AL/PEI in NLCs appears a viable drug delivery strategy for augmenting oral bioavailability of this clinically relevant bisphosphonate drug and, simultaneously, increase gastrointestinal safety.
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http://dx.doi.org/10.1016/j.ijpharm.2017.10.064DOI Listing
January 2018

Mucoadhesive tablets for the vaginal delivery of progesterone: in vitro evaluation and pharmacokinetics/pharmacodynamics in female rabbits.

Drug Dev Ind Pharm 2018 Feb 23;44(2):224-232. Epub 2017 Oct 23.

a Department of Pharmaceutics, Faculty of Pharmacy , Assiut University , Assiut , Egypt.

Objective: To develop mucoadhesive tablets for the vaginal delivery of progesterone (P4) to overcome its low oral bioavailability resulting from drug hydrophobicity and extensive hepatic metabolism.

Methods: The tablets were prepared using mixtures of P4/Pluronic F-127 solid dispersion and different mucoadhesive polymers. The tablets physical properties, swelling index, mucoadhesion and drug release kinetics were evaluated. P4 pharmacokinetic and pharmacodynamic properties were evaluated in female rabbits and compared with vaginal micronized P4 tablets and intramuscular (IM) P4 injection, respectively.

Results: The tablets had satisfactory physical properties and their swelling, in vitro mucoadhesion force and ex vivo mucoadhesion time were dependent on tablet composition. Highest swelling index and mucoadhesion time were detected for tablets containing 20% chitosan-10% alginate mixture. Most tablets exhibited burst release (∼25%) during the first 2 h but sustained the drug release for ∼48 h. In vivo study showed that chitosan-alginate mucoadhesive tablets had ∼2-fold higher P4 mean residence time (MRT) in the blood and 5-fold higher bioavailability compared with oral P4. Further, same tablets showed 2-fold higher myometrium thickness in rabbit uterus compared with IM P4 injection.

Conclusion: These results confirm the potential of these mucoadhesive vaginal tablets to enhance P4 efficacy and avoid the side effects associated with IM injection.
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http://dx.doi.org/10.1080/03639045.2017.1386203DOI Listing
February 2018

Development and in vivo evaluation of chitosan beads for the colonic delivery of azathioprine for treatment of inflammatory bowel disease.

Eur J Pharm Sci 2017 Nov 19;109:269-279. Epub 2017 Aug 19.

Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut, Egypt.

Azathioprine is a highly efficient immunosuppressant drug used for treatment of inflammatory bowel disease (IBD). Systemic administration of azathioprine results in delayed therapeutic effect and serious adverse reactions. In the current study, we have developed, for the first time, colon-targeted chitosan beads for delivery of azathioprine in colitis rabbit model. Several characterizations were performed for the azathioprine-loaded beads (e.g. drug encapsulation efficiency, drug loading capacity, yield, size, shape and compatibility with other ingredients). The in vitro release profiles of acid-resistant capsules filled with azathioprine-loaded beads showed that most of azathioprine was released in IBD colon simulating medium. The therapeutic effects of azathioprine-loaded beads and azathioprine crude drug were examined on acetic acid-induced colitis rabbit model. Improved therapeutic outcomes were observed in the animals treated with the azathioprine-loaded beads, as compared to the untreated animal controls and the animals treated with the azathioprine free drug, based on the clinical activity score, index of tissue edema, mortality rate, colon macroscopic score and colon histopathological features. In the animals treated with the azathioprine-loaded beads, the levels of the inflammatory mediators, myeloperoxidase enzyme and tumor necrosis factor-α, were significantly reduced to levels similar to those observed in the normal rabbits. Furthermore, the activities of the antioxidant enzymes, superoxide dismutase and catalase, were restored considerably in the animals treated with the drug-loaded beads. The azathioprine-loaded beads developed in the current study might have great potential in the management of IBD.
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http://dx.doi.org/10.1016/j.ejps.2017.08.025DOI Listing
November 2017

Gold nanoparticles capped with benzalkonium chloride and poly (ethylene imine) for enhanced loading and skin permeability of 5-fluorouracil.

Drug Dev Ind Pharm 2017 Nov 21;43(11):1780-1791. Epub 2017 Jun 21.

a Department of Pharmaceutics, Faculty of Pharmacy , Assiut University , Assiut , Egypt.

Objective: To enhance 5-fluorouracil (5-FU) permeability through the skin by loading onto gold nanoparticles (GNPs) capped with two cationic ligands, benzalkonium chloride (BC) or poly (ethylene imine) (PEI). Whereas 5-FU has excellent efficacy against many cancers, its poor permeability through biological membranes and several adverse effects limit its clinical benefits. BC and PEI were selected to stabilize GNPs and to load 5-FU through ionic interactions.

Methods: 5-FU/BC-GNPs and 5-FU/PEI-GNPs were prepared at different 5-FU/ligand molar ratios and different pH values and were evaluated using different techniques. GNPs stability was tested as a function of salt concentration and storage time. 5-FU release from BC- and PEI-GNPs was evaluated as a function of solution pH. Ex vivo permeability studies of different 5-FU preparations were carried out using mice skin.

Results: 5-FU-loaded GNPs size and surface charge were dependent on the 5-FU/ligand molar ratios. 5-FU entrapment efficiency and loading capacity were dependent on the used ligand, 5-FU/ligand molar ratio and solution pH. Maximum drug entrapment efficiency of 59.0 ± 1.7% and 46.0 ± 1.1% were obtained for 5-FU/BC-GNPs and 5-FU/PEI-GNPs, respectively. 5-FU-loaded GNPs had good stability against salinity and after storage for 4 months at room temperature and at 4 °C. In vitro 5-FU release was pH- and ligand-dependent where slower release was observed at higher pH and for 5-FU/BC-GNPs. 5-FU permeability through mice skin was significantly higher for drug-loaded GNPs compared with drug-ligand complex or drug aqueous solution.

Conclusion: Based on these results, BC- and PEI-GNPs might find applications as effective topical delivery systems of 5-FU.
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http://dx.doi.org/10.1080/03639045.2017.1339082DOI Listing
November 2017

Enalapril maleate orally disintegrating tablets: tableting and in vivo evaluation in hypertensive rats.

Pharm Dev Technol 2018 Jun 29;23(5):496-503. Epub 2017 May 29.

c Department of Pharmaceutics , Faculty of Pharmacy, Assiut University , Assiut , Egypt.

The aim of this study was to develop orally disintegrating tablets (ODTs) for enalapril maleate (EnM) to facilitate its administration to the elderly or other patients having dysphagia. Compatibility between EnM and various excipients was studied using differential scanning calorimetry. ODTs of EnM were prepared by direct compression of EnM mixtures with various superdisintegrants. The tablets were evaluated for physical properties including drug content, hardness, friability, disintegration time, wetting time, and drug release. The antihypertensive effect of the optimum EnM ODTs was evaluated in vivo in hypertensive rats and compared with commercial EnM formulation. EnM ODTs had satisfactory results in terms of drug content and friability. Tablet wetting and disintegration were fast and dependent on the used superdisintegrant where croscarmellose showed the fastest wetting and disintegration time of ∼7 s. EnM release from the tablets was rapid where complete release was obtained in 10-15 min. Selected EnM ODTs rapidly and efficiently reduced the rat's blood pressure to its normal value within 1 h, compared with 4 h for EnM commercial formulation. These results confirm that EnM ODTs could find application in the management of hypertension in the elderly or other patients having dysphagia.
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http://dx.doi.org/10.1080/10837450.2017.1329318DOI Listing
June 2018

Nanoparticles as safe and effective delivery systems of antifungal agents: Achievements and challenges.

Authors:
Ghareb M Soliman

Int J Pharm 2017 May 19;523(1):15-32. Epub 2017 Mar 19.

Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut, 71526, Egypt; Department of Pharmaceutics, Faculty of Pharmacy, University of Tabuk, Tabuk, Saudi Arabia. Electronic address:

Invasive fungal infections are becoming a major health concern in several groups of patients leading to severe morbidity and mortality. Moreover, cutaneous fungal infections are a major cause of visits to outpatient dermatology clinics. Despite the availability of several effective agents in the antifungal drug arena, their therapeutic outcome is less than optimal due to limitations related to drug physicochemical properties and toxicity. For instance, poor aqueous solubility limits the formulation options and efficacy of several azole antifungal drugs while toxicity limits the benefits of many other drugs. Nanoparticles hold great promise to overcome these limitations due to their ability to enhance drug aqueous solubility, bioavailability and antifungal efficacy. Further, drug incorporation into nanoparticles could greatly reduce its toxicity. Despite these interesting nanoparticle features, there are only few marketed nanoparticle-based antifungal drug formulations. This review sheds light on different classes of nanoparticles used in antifungal drug delivery, such as lipid-based vesicles, polymeric micelles, solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsions and dendrimers with emphasis on their advantages and limitations. Translation of these nanoformulations from the lab to the clinic could be facilitated by focusing the research on overcoming problems related to nanoparticle stability, drug loading and high cost of production and standardization.
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http://dx.doi.org/10.1016/j.ijpharm.2017.03.019DOI Listing
May 2017

Solubilization and Enhancement of Ex Vivo Vaginal Delivery of Progesterone Using Solid Dispersions, Inclusion Complexes and Micellar Solubilization.

Curr Drug Deliv 2018 ;15(1):110-121

Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut, 71526. Egypt.

Background: Progesterone (PG), a natural female sex hormone is used clinically in menopausal hormone replacement therapy and to control reproductive functions. Its very limited aqueous solubility results in reduced oral bioavailability and low patient compliance when administered in high doses. The aim of this study was to enhance PG aqueous solubility and vaginal delivery using solid dispersion, inclusion complex and micellar solubilization techniques.

Methods: PG solid dispersions and inclusion complexes were prepared by solvent evaporation method using different polymers, such as cyclodextrins, polyvinyl pyrrolidone (PVP), poly (ethylene glycol) 6000, Pluronic® F-127 and Pluronic® F-68. PG was also incorporated into polymeric micelles of Pluronic® F-127, Pluronic® F- 68, Brij®35 and Myrj®52. The prepared solid dispersions, inclusion complexes and micelles were characterized using different techniques. Drug permeability across rabbit vaginal mucosa was also studied.

Results: Dissolution studies of PG solid dispersions showed that the highest drug dissolution rate was achieved at PG/polymer weight ratio of 5:5. Further, complete drug dissolution was obtained for PG/Pluronic® F-127 solid dispersion after 15 min compared to 42% dissolution for the drug alone. Brij®35 micelles had a drug loading capacity ~15%, which increased the drug aqueous solubility by more than 20 folds. PG permeability coefficients through rabbit vaginal mucosa for PG/Brij®35 micelles and PG/Pluronic® F-127 micelles were ~ two times higher than that of the drug alone.

Conclusion: These results confirm that Brij®35 and Pluronic® F-127 micelles are promising carriers to overcome PG shortcomings through enhancing its aqueous solubility and vaginal permeability.
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http://dx.doi.org/10.2174/1567201814666170320142136DOI Listing
August 2018

Thermosensitive bioadhesive gels for the vaginal delivery of sildenafil citrate: in vitro characterization and clinical evaluation in women using clomiphene citrate for induction of ovulation.

Drug Dev Ind Pharm 2017 Mar 14;43(3):399-408. Epub 2016 Nov 14.

c Department of Obstetrics and Gynecology, Faculty of Medicine , Assiut University , Assiut , Egypt.

Objective: The objective of this study is to develop and characterize in situ thermosensitive gels for the vaginal administration of sildenafil as a potential treatment of endometrial thinning occurring as a result of using clomiphene citrate for ovulation induction in women with type II eugonadotrophic anovulation. While sildenafil has shown promising results in the treatment of infertility in women, the lack of vaginal pharmaceutical preparation and the side effects associated with oral sildenafil limit its clinical effectiveness.

Methods: Sildenafil citrate in situ forming gels were prepared using different grades of Pluronic (PF-68 and PF-127). Mucoadhesive polymers as sodium alginate and hydroxyethyl cellulose were added to the gels in different concentrations and the effect on gel properties was studied. The formulations were evaluated in terms of viscosity, gelation temperature (T), mucoadhesion properties, and in vitro drug release characteristics. Selected formulations were evaluated in women with clomiphene citrate failure due to thin endometrium (Clinicaltrial.gov identifier NCT02766725).

Results: The T decreased with increasing PF-127 concentration and it was modulated by addition of PF-68 to be within the acceptable range of 28-37 °C. Increasing Pluronic® concentration increased gel viscosity and mucoadhesive force but decreased drug release rate. Clinical results showed that the in situ sildenafil vaginal gel significantly increased endometrial thickness and uterine blood flow with no reported side effects. Further, these results were achieved at lower frequency and duration of drug administration.

Conclusion: Sildenafil thermosensitive vaginal gels might result in improved potential of pregnancy in anovulatory patients with clomiphene citrate failure due to thin endometrium.
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http://dx.doi.org/10.1080/03639045.2016.1254239DOI Listing
March 2017

Gold nanoparticles enhance 5-fluorouracil anticancer efficacy against colorectal cancer cells.

Int J Pharm 2016 Nov 29;513(1-2):648-658. Epub 2016 Sep 29.

Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut 71526, Egypt.

5-Fluorouracil (5-FU), an antimetabolite drug, is extensively used in the treatment solid tumors. However, its severe side effects limit its clinical benefits. To enhance 5-FU anticancer efficacy and reduce its side effects it was loaded onto gold nanoparticles (GNPs) using two thiol containing ligands, thioglycolic acid (TGA) and glutathione (GSH). The GNPs were prepared at different 5-FU/ligand molar ratios and evaluated using different techniques. Anticancer efficacy of 5-FU/GSH-GNPs was studied using flow cytometry in cancerous tissue obtained from patients having colorectal cancer. The GNPs were spherical in shape and had a size of ∼9-17nm. Stability of the GNPs and drug release were studied as a function of salt concentration and solution pH. Maximum 5-FU loading was achieved at 5-FU/ligand molar ratio of 1:1 and 2:1 for TGA-GNPs and GSH-GNPs, respectively. GNPs coating with pluronic F127 improved their stability against salinity. 5-FU release from GNPs was slow and pH-dependent. 5-FU/GSH-GNPs induced apoptosis and stopped the cell cycle progression in colorectal cancer cells. They also had a 2-fold higher anticancer effect compared with free 5-FU. These results confirm the potential of GNPs to enhance 5-FU anticancer efficacy.
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http://dx.doi.org/10.1016/j.ijpharm.2016.09.076DOI Listing
November 2016

Enhanced skin deposition and delivery of voriconazole using ethosomal preparations.

J Liposome Res 2018 Mar 19;28(1):14-21. Epub 2016 Oct 19.

c Department of Pharmaceutics , Faculty of Pharmacy, University of Tabuk , Tabuk , Saudi Arabia.

Despite its broad-spectrum antifungal properties, voriconazole has many side effects when administered systemically. The aim of this work was to develop an ethosomal topical delivery system for voriconazole and test its potential to enhance the antifungal properties and skin delivery of the drug. Voriconazole was encapsulated into various ethosomal preparations and the effect of phospholipid and ethanol concentrations on the ethosomes properties were evaluated. The ethosomes were evaluated for drug encapsulation efficiency, particle size and morphology and antifungal efficacy. Drug permeability and deposition were tested in rat abdominal skin. Drug encapsulation efficiency of up to 46% was obtained and it increased with increasing the phospholipid concentration, whereas the opposite effect was observed for the ethanol concentration. The ethosomes had a size of 420-600 nm and negative zeta potential. The particle size of the ethosomes increased by increasing their ethanol content. The ethosomes achieved similar inhibition zones against Aspergillus flavus at a 2-fold lower drug concentration compared with drug solution in dimethyl sulfoxide. The ex vivo drug permeability through rat abdominal skin was ∼6-fold higher for the ethosomes compared with the drug hydroalcoholic solution. Similarly, the amount of drug deposited in the skin was higher for the ethosomes and was dependent on the ethanol concentration of the ethosomes. These results confirm that voriconazole ethosomal preparations are promising topical delivery systems that can enhance the drug antifungal efficacy and improve its skin delivery.
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http://dx.doi.org/10.1080/08982104.2016.1239636DOI Listing
March 2018

Development and in vitro/in vivo evaluation of Zn-pectinate microparticles reinforced with chitosan for the colonic delivery of progesterone.

Drug Deliv 2016 Sep 8;23(7):2541-2554. Epub 2015 Apr 8.

a Department of Pharmaceutics, Faculty of Pharmacy , Assiut University , Assiut , Egypt.

The colon is a promising target for drug delivery owing to its long transit time of up to 78 h, which is likely to increase the time available for drug absorption. Progesterone has a short elimination half-life and undergoes extensive first-pass metabolism, which results in very low oral bioavailability (∼25%). To overcome these shortcomings, we developed an oral multiparticulate system for the colonic delivery of progesterone. Zn-pectinate/chitosan microparticles were prepared by ionotropic gelation and characterized for their size, shape, weight, drug entrapment efficiency, mucoadhesion and swelling behavior. The effect of cross-linking pH, cross-linking time and chitosan concentration on progesterone release were also studied. Spherical microparticles having a diameter of 580-720 µm were obtained. Drug entrapment efficiency of ∼75-100% was obtained depending on the microparticle composition. Microparticle mucoadhesive properties were dependent on the pectin concentration, as well as the cross-linking pH. Progesterone release in simulated gastric fluids was minimal (3-9%), followed by burst release at pH 6.8 and a sustained phase at pH 7.4. The in vivo study revealed that the microparticles significantly increased progesterone residence time in the plasma and increased its relative bioavailability to ∼168%, compared to the drug alone. This study confirms the potential of Zn-pectinate/chitosan microparticles as a colon-specific drug delivery system able to enhance the oral bioavailability of progesterone or similar drugs.
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http://dx.doi.org/10.3109/10717544.2015.1028602DOI Listing
September 2016

Amidated pectin/sodium carboxymethylcellulose microspheres as a new carrier for colonic drug targeting: Development and optimization by factorial design.

Carbohydr Polym 2016 Nov 6;153:526-534. Epub 2016 Aug 6.

Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut 71526, Egypt. Electronic address:

The colon is a promising site for drug targeting owing to its long transit time and mild proteolytic activity. The aim of this study was to prepare new low methoxy amidated pectin/NaCMC microspheres cross-linked by a mixture of Zn(2+) and Al(3+) ions and test their potential for colonic targeting of progesterone. A 2(4) factorial design was carried out to optimize the preparation conditions. High drug entrapment efficiency (82-99%) was obtained and it increased with increasing drug concentration but decreased with increasing polymer concentration. Drug release rate was directly proportional to the microsphere drug content and inversely related to Al(3+) ion concentration. Drug release was minimal during the first 3h but was significantly improved in the presence of 1% rat caecal contents, confirming the microsphere potential for colonic delivery. The microspheres achieved >2.3-fold enhancement of colonic progesterone permeability. These results confirm the viability of the produced microspheres as colon-targeted drug delivery vehicle.
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http://dx.doi.org/10.1016/j.carbpol.2016.08.018DOI Listing
November 2016

Physically cross-linked hydrogels of β -cyclodextrin polymer and poly(ethylene glycol)-cholesterol as delivery systems for macromolecules and small drug molecules.

Curr Drug Deliv 2015 ;12(4):415-24

Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut, 71526, Egypt.

An injectable hydrogel based on the inclusion complexation of polymerized β-cyclodextrin (pβ-CD) and cholesterol terminated poly(ethylene glycol) (PEG-chol) was developed and used as a delivery system for both macromolecules and small drugs. The hydrogel was characterized by different analyses including X-ray diffraction, differential scanning calorimetry and scanning electron microscopy. The effects of pβ-CD/PEG-chol ratio and PEG-chol architecture on the hydrogel properties were also investigated. Cytotoxicity of the hydrogel was evaluated in NIH 3T3 fibroblasts using MTS assay. The hydrogel had an elastic behavior even at high temperature since the gelation temperature was observed at 68 °C. The highest hydrogel strength and stability were observed for the 8-armed PEG-chol at a pβ-CD/PEG-chol ratio of 1:1, w/w. Hydrogel degradation in phosphate buffered saline occurred by gradual erosion over the course of two months. IgG, a model hydrophilic macromolecule and riluzole, a model hydrophobic small drug were incorporated into the hydrogel and quantitatively released in a sustained fashion. The released IgG maintained its bioactivity confirming the absence of deleterious effects on protein structure during loading and release. The hydrogels showed no toxicity on NIH 3T3 fibroblasts confirming their biocompatibility. These results confirm the potential of pβ-CD/PEG-chol hydrogel as a versatile delivery system for drugs of different molecular weights and nature.
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http://dx.doi.org/10.2174/1567201812666150326113331DOI Listing
May 2016

Hydrocaffeic acid-chitosan nanoparticles with enhanced stability, mucoadhesion and permeation properties.

Eur J Pharm Biopharm 2014 Nov 2;88(3):1026-37. Epub 2014 Oct 2.

Faculty of Dentistry, McGill University, Montreal, QC, Canada. Electronic address:

Catechol-containing molecules, such as hydrocaffeic acid (HCA) have been shown to increase the mucoadhesion of several polymers. We report here a simple and bioinspired approach to enhance chitosan (CS) mucoadhesion and stabilize it in nanoparticulate form by preparing HCA-CS conjugates. HCA-CS conjugates containing 6 and 15mol% HCA were synthesized and characterized by FT-IR, (1)H NMR and UV-vis spectrophotometry. HCA-CS nanoparticles prepared by ionic gelation with sodium tripolyphosphate (TPP) ranged in size between 100 and 250nm depending on the polymer and TPP/CS weight ratio. In contrast to CS nanoparticles, which aggregate at pH>6.5, HCA-CS nanoparticles did not show any sign of aggregation or precipitation over the 4-10 pH range and maintain their size. Unexpectedly, HCA-CS nanoparticles also maintained their size and polydispersity index at pH 7.4 and NaCl concentrations of up to 500mM. Partial oxidation of HCA resulted in nanoparticle cross-linking and improved stability at pH<4. HCA-CS mucoadhesion to rabbit small intestine was 6 times higher than unmodified CS. CS and HCA-CS nanoparticles were able to induce reversible tight junction opening in Caco-2 cell monolayers. Tight junction opening facilitated the permeability of a model hydrophilic molecule, fluorescein isothiocyanate-labeled dextran (FD4) and was 3 times higher in the cells treated with HCA-CS 15% nanoparticles compared to control groups. HCA-CS conjugates were found to be excellent candidates for stable nanodelivery systems with enhanced oral absorption of hydrophilic molecules.
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http://dx.doi.org/10.1016/j.ejpb.2014.09.003DOI Listing
November 2014

Poly(ethylene glycol)-block-poly(ε-caprolactone) nanomicelles for the solubilization and enhancement of antifungal activity of sertaconazole.

Curr Drug Deliv 2014 ;11(6):753-62

Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut, 71526, Egypt.

Sertaconazole nitrate is a broad spectrum imidazole antifungal agent with antibacterial and anti-inflammatory properties. However, its lipophilic nature and very poor aqueous solubility limit its use in the clinic. The aim of this study was to develop and characterize poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-b-PCL) polymeric nanomicelles for the solubilization and enhancement of sertaconazole antifungal activity. Sertaconazole was incorporated into PEG-b- PCL polymeric nanomicelles by a co-solvent evaporation method and micelle size, drug loading capacity and drug release properties were determined. The antifungal properties of nanomicelle-loaded drug were evaluated in Fusarium miscanthi, Microsporum canis, and Trichophyton mentagrophytes isolated, respectively from fungal keratitis, ringworm, and tinea corporis. PEG-b-PCL formed nanomicelles in aqueous solution with a diameter ranging from 40-80 nm, depending on the polymer composition and level of drug loading. Drug loading properties of the nanomicelles were dependent on the PCL block molecular weight and drug/polymer weight feed ratio. Drug encapsulation efficiency of up to 85% was achieved and this resulted in more than 80-fold enhancement in sertaconazole aqueous solubility at polymer concentration of 0.2%. Drug release studies showed an initial burst release followed by sustained drug release for 72 hours. In vitro antimycotic studies showed that nanomicelle-incorporated sertaconazole inhibited fungal growth in a concentration dependent manner. Further, it was more effective than the free drug in inhibiting the growth of Fusarium miscanthi and Microsporum canis. These results confirm the utility of PEG-b-PCL nanomicelles in enhancing the aqueous solubility and antifungal activity of sertaconazole or other similar antifungal drugs.
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http://dx.doi.org/10.2174/1567201811666140605151923DOI Listing
September 2015

Miktoarm star polymer based multifunctional traceable nanocarriers for efficient delivery of poorly water soluble pharmacological agents.

Macromol Biosci 2014 Sep 6;14(9):1312-24. Epub 2014 Jun 6.

Department of Chemistry, McGill University, 801 Sherbrooke St. West, Montreal, Quebec, Canada, H3A 0B8; Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, Quebec, Canada, H3G 1Y6; Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, 71526, Assiut, Egypt.

A versatile methodology to develop an inherently fluorescent and thus traceable multifunctional nanodelivery platform based on miktoarm polymers is reported. Miktoarm stars containing covalently linked tetraiodofluorescein dye, polyethylene glycol, and polycaprolactone self-assemble into micelles, and integrate multiple functions including fluorescent tags for imaging, a hydrophobic core for drug incorporation, and a hydrophilic corona for micelle stabilization. Curcumin, a pleiotropic but very poorly water-soluble drug, is loaded into these micelles with an efficiency of 25-60 wt%. It leads to a 25 000-fold increase in its aqueous solubility, and a sustained release over a period of 7 d. These micelles are rapidly internalized into murine J774A.1 macrophages, and accumulated into discrete cellular compartments, whereas the free and physically encapsulated dye is diffused in the cytoplasm. Curcumin-loaded micelles reduce lipopolysaccharide-induced nitric oxide release. The studies establish miktoarm star based nanocarriers as highly efficient in tracking their fate and expanding the scope of pharmacological agents with limited utility in experimental medicine.
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http://dx.doi.org/10.1002/mabi.201400123DOI Listing
September 2014

Mollusk glue inspired mucoadhesives for biomedical applications.

Langmuir 2012 Oct 18;28(39):14010-7. Epub 2012 Sep 18.

Department of Mining and Materials Engineering, McGill University, Montreal, QC, Canada.

Chitosan (CH), partially N-deacetylated chitin, is a biodegradable and biocompatible polymer that has shown great potential in drug delivery and tissue engineering applications. Although bioadhesive, CH has limited mucoadhesion in wet conditions due to weak interactions with biological surfaces. DOPA (3,4-dihydroxy-L-phenylalanine), a catechol-containing molecule naturally present in marine mussel foot proteins, has been shown to increase the mucoadhesion of several polymers. We report here a simple and bioinspired approach to enhance CH mucoadhesion in wet conditions by preparing mixed hydrogels including CH and different catechol-containing compounds, namely DOPA, hydrocaffeic acid (HCA), and dopamine (DA). We characterized the hydrogels for their swelling, release kinetics of the catechol compounds, and mucoadhesive strength to rabbit small intestine. The swelling of the hydrogels was pH dependent with maximum swelling at pH 1. The hydrogel swelling was higher in the presence of the DOPA and DA but lower in the presence of HCA. HCA/CH hydrogel also showed the slowest catechol release, most likely due to electrostatic interactions between CH and HCA. Lower hydrogel swelling and slower HCA release resulted in increased mucoadhesion: HCA/CH showed more than 2-fold enhancement of mucoadhesion to rabbit small intestine compared to CH alone. Since it is known that catechol compounds can be oxidized, we analyzed the oxidation of DOPA, HCA, and DA at different pH values and its effect on mucoadhesion. We found that oxidation occurring before contact with the intestinal mucosa did not improve mucoadhesion, while oxidation occurring during the contact further increased the mucoadhesion of HCA/CH hydrogels. These results show that mucoadhesion of CH hydrogels can be increased with a simple bioinspired approach, which has the potential to be applied to other polymers since it does not require any chemical modification.
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http://dx.doi.org/10.1021/la3025414DOI Listing
October 2012

Modulation of inflammatory signaling and cytokine release from microglia by celastrol incorporated into dendrimer nanocarriers.

Nanomedicine (Lond) 2012 Aug 4;7(8):1149-65. Epub 2012 Apr 4.

Department of Pharmacology & Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, QC, H3G 1Y6, Canada.

Aim: This study investigates the capacity of a potent anti-inflammatory nanomedicine, celastrol, incorporated into poly(amidoamine) dendrimers, to inhibit endotoxin-mediated signaling in microglia.

Materials & Methods: Celastrol was incorporated into amino (Cel/G4-NH(2)) and hydroxyl (Cel/G4-OH) terminus poly(amidoamine) (G4) dendrimers. Cell viability, release of nitric oxide, IL-6, TNF-α and activation of MAPK (e.g., p38 and JNK) and NF-κB were assessed in endotoxin (i.e., lipopolysaccharide) stimulated microglial cells.

Results: G4-OH and G4-NH(2) increased celastrol aqueous solubility by seven- and 12-fold, respectively. G4-OH and Cel/G4-OH suppressed lipopolysaccharide-mediated release of proinflammatory mediators, such as nitric oxide and IL-6, but not TNF-α, without reducing microglial cell viability, while Cel/G4-NH(2) potentiated cytotoxicity and cytokine release. Blockade of proinflammatory signaling was accompanied by attenuation of p38 MAPK activation.

Conclusion: This study supports the potential use of poly(amidoamine) dendrimers for effective anti-inflammatory therapy in the chronically inflamed CNS.
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http://dx.doi.org/10.2217/nnm.12.16DOI Listing
August 2012

Design and evaluation of multifunctional nanocarriers for selective delivery of coenzyme Q10 to mitochondria.

Biomacromolecules 2012 Jan 16;13(1):239-52. Epub 2011 Dec 16.

Department of Chemistry, McGill University, Montreal, Quebec, H3A 2K6, Canada.

Impairments of mitochondrial functions have been associated with failure of cellular functions in different tissues, leading to various pathologies. We report here a mitochondria-targeted nanodelivery system for coenzyme Q10 (CoQ10) that can reach mitochondria and deliver CoQ10 in adequate quantities. Multifunctional nanocarriers based on ABC miktoarm polymers (A = poly(ethylene glycol (PEG), B = polycaprolactone (PCL), and C = triphenylphosphonium bromide (TPPBr)) were synthesized using a combination of click chemistry with ring-opening polymerization, self-assembled into nanosized micelles, and were employed for CoQ10 loading. Drug loading capacity (60 wt %), micelle size (25-60 nm), and stability were determined using a variety of techniques. The micelles had a small critical association concentration and were colloidally stable in solution for more than 3 months. The extraordinarily high CoQ10 loading capacity in the micelles is attributed to good compatibility between CoQ10 and PCL, as indicated by the low Flory-Huggins interaction parameter. Confocal microscopy studies of the fluorescently labeled polymer analog together with the mitochondria-specific vital dye label indicated that the carrier did indeed reach mitochondria. The high CoQ10 loading efficiency allowed testing of micelles within a broad concentration range and provided evidence for CoQ10 effectiveness in two different experimental paradigms: oxidative stress and inflammation. Combined results from chemical, analytical, and biological experiments suggest that the new miktoarm-based carrier provides a suitable means of CoQ10 delivery to mitochondria without loss of drug effectiveness. The versatility of the click chemistry used to prepare this new mitochondria-targeting nanocarrier offers a widely applicable, simple, and easily reproducible procedure to deliver drugs to mitochondria or other intracellular organelles.
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http://dx.doi.org/10.1021/bm201538jDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4911219PMC
January 2012

Dendrimers and miktoarm polymers based multivalent nanocarriers for efficient and targeted drug delivery.

Chem Commun (Camb) 2011 Sep 9;47(34):9572-87. Epub 2011 Jun 9.

Department of Chemistry, McGill University, 801 Sherbrooke St. West, Montreal, Quebec, H3A 2K6, Canada.

The delivery of biologically active agents to the desired site in the body and intracellular organelles is still a big challenge despite efforts made for more than five decades. With the elaboration of synthetic methodologies to branched and hyperbranched macromolecules such as miktoarm stars and dendrimers, the focus has shifted to nanocarriers able to release and direct drug molecules to a desired location in a controlled manner. We present here recent developments in the field of targeted drug delivery with a focus on two specific macromolecular nanocarriers, dendrimers and miktoarm stars, and provide examples of these nanocarriers tested in different biological systems. A particular attraction of miktoarm stars is their versatility in achieving superior drug loading within their self-assembled structures. Advantages of dendrimers over linear polymers are that the former provide a platform for development of multivalent and multifunctional nanoconjugates, in addition to their ability to accommodate a large number of molecules inside, or at their surfaces.
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http://dx.doi.org/10.1039/c1cc11981hDOI Listing
September 2011

Short ligands affect modes of QD uptake and elimination in human cells.

ACS Nano 2011 Jun 3;5(6):4909-18. Epub 2011 Jun 3.

Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Room 1314, McIntyre Medical Sciences Building, Montreal, QC, H3G 1Y6, Canada.

In order to better understand nanoparticle uptake and elimination mechanisms, we designed a controlled set of small, highly fluorescent quantum dots (QDs) with nearly identical hydrodynamic size (8-10 nm) but with varied short ligand surface functionalization. The properties of functionalized QDs and their modes of uptake and elimination were investigated systematically by asymmetrical flow field-flow fractionation (AF4), confocal fluorescence microscopy, flow cytometry (FACS), and flame atomic absorption (FAA). Using specific inhibitors of cellular uptake and elimination machinery in human embryonic kidney cells (Hek 293) and human hepatocellular carcinoma cells (Hep G2), we showed that QDs of the same size but with different surface properties were predominantly taken up through lipid raft-mediated endocytosis, however, to significantly different extents. The latter observation infers the contribution of additional modes of QD internalization, which include X-AG cysteine transporter for cysteine-functionalized QDs (QD-CYS). We also investigated putative modes of QD elimination and established the contribution of P-glycoprotein (P-gp) transporter in QD efflux. Results from these studies show a strong dependence between the properties of QD-associated small ligands and modes of uptake/elimination in human cells.
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http://dx.doi.org/10.1021/nn201009wDOI Listing
June 2011

Tailoring the efficacy of nimodipine drug delivery using nanocarriers based on A2B miktoarm star polymers.

Biomaterials 2010 Nov 5;31(32):8382-92. Epub 2010 Aug 5.

Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, Quebec H3G 1Y6, Canada.

We report a nanocarrier based on A(2)B type miktoarm polymers (A=polyethylene glycol (PEG); B=polycaprolactone (PCL)) for nimodipine (NIM), a hydrophobic drug with very poor aqueous solubility that is commonly prescribed for the prevention and treatment of delayed ischemic neurological disorders. The A(2)B star polymers were constructed on a core with orthogonal functionalities that facilitated the performance of "click" chemistry followed by ring-opening polymerization. These star polymers assemble into spherical micelles into which NIM can be easily loaded by the co-solvent evaporation method. The micelles obtained from the star polymer PEG775(2)-PCL5800 showed NIM encapsulation efficiency of up to 78 wt% at a feed weight ratio of 5.0%. The loading efficiency of the micelles was dependent on the length of the PCL arm in the A(2)B miktoarm polymers. Aqueous solubility of NIM was increased by approximately 200 fold via micellar encapsulation. The in vitro release of NIM from the micelles was found to occur at a much slower rate than from its solution. Lipopolysaccharide induced nitric oxide production in N9 microglia cells was reduced in the presence of micelle-encapsulated NIM, as well as in the presence of micelles alone. The treatment of microglia with micelle-encapsulated NIM reduced the release of TNF-alpha, a pro-inflammatory cytokine. These results suggest that NIM-loaded miktoarm micelles could be useful in the treatment of neuroinflammation.
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http://dx.doi.org/10.1016/j.biomaterials.2010.07.039DOI Listing
November 2010